I'm using the fec0 of the iMX287 with 10M/Half duplex mode,but sometimes the fec0 will enter error state with the error message is "eth0: tx queue full!",and this state will keep on until I send "ifconfig eth0 down" and "ifconfig eth0 up".After these two commands,the fec0 will word correctly.I find the location of the error message "eth0: tx queue full!" is in the function of fec_enet_start_xmit in /drivers/net/fec.c, the resaon is the status bit BD_ENET_TX_READY is set. What's this bit mean? and in what condition this bit will be set? and when this bit is set, where and how to reset it?